on constant tectonic loading are as good as or better Other geophysical measurements may also bere- than time-varying earthquake likelihood models ted to earthquake occurrence, and such relationships determinedfrom the evolving stress ?eld. are examinedin some of the papers herein. ITABA et al. One approach to understanding earthquakes isto compare groundwater and crustal deformation to create synthetic earthquake catalogues using certain seismicity recorded on newly installed stations to test assumptions regarding the physics of the process to previouslyobserved preseismicchanges inShikoku see what features of real catalogues can be explained and theKii Peninsula prior to earthquakes in Tonankai by variations in physical properties. SMITH and and Nankai, Japan. They ?nd strainchanges due to DIETERICH takethis approach and model aftershock slow slip events on the plate boundary, but do not ?nd sequences using 3-D stress heterogeneity in the form signi?cant changes in groundwater at that time. of Coulomb static stress change analysisand rate- We conclude the volume with another comparison state seismicity equations calculatedin regions of of seismicity and GPS.
OGATA compares anomalies of geometrically complex faults. Their syntheticmodels seismic activity with transient crustaldeformations match severalfeatures of real catalogues such as preceding the 2005 M 7.0 earthquake west of - earthquakeclustering and Omoridecay,and the kuoka, Japan, concluding that aseismicsliptriggered presence of earthquakes in regions where simpler changes in seismicity rates as well as in GPS record- Coulomb stress modelling predicts "stress shadows" ings during the ten years leading up to the earthquake.